Mystery of the moving rocks

Geologists have been able to explain much about the way the earth was formed, how its mountain ranges and basins rose and sank from shifting and stretching tectonic plates, and other formerly enduring mysetries of the ages. But there's one thing, strange and seemingly inconsequential -- albeit fascinating -- that science hasn't been able to explain.

Deep in the basin of foreboding Death Valley is a flat area locals call "The Racetrack," for one reason: rocks and boulders which dot the area seem to be engaged in a strange (and unspeakably slow) race across the dessicated mud. Long furrows in the mud are giveaways of the rocks' motion, which is usually zigzagging but sometimes form complete circles, but what puzzles experts is just how they move. Some think the wind has something to do with it -- though some of the rocks weigh as much as 700 pounds -- while others guess that rare instances of rain in Death Valley turn the basin into a slick, lubricated track that would allow the wind to move the rocks more easily.

But despite decades of research -- and even GPS tracking of individual rocks -- nobody knows for sure. For now, at least, conspiracy theorists, UFO believers and other amateur explainers (even you!) still have a shot at being right.

Christmas trees aren't for everyone. Some people can't fit a fir inside their cramped abodes, while others are turned off by the expense, or by the idea of bugs hitchhiking their way inside. Fake trees are always an option, but a new trend sweeping Instagram—pineapples as mini-Christmas "trees"—might convince you to forego the forest vibe for a more tropical aesthetic.

As Thrillist reports, the pineapple-as-Christmas-tree idea appears to have originated on Pinterest before it, uh, ripened into a social media sensation. Transforming a pineapple into a Halloween “pumpkin” requires carving and tea lights, but to make the fruit festive for Christmas all one needs are lights, ornaments, swaths of garland, and any other tiny tchotchkes that remind you of the holidays. The final result is a tabletop decoration that's equal parts Blue Hawaii and Miracle on 34th Street.

In need of some decorating inspiration? Check out a variety of “Christmas tree” pineapples below.